Are squat lobsters really lobsters?

Squat lobsters look like lobsters, but they are actually more closely related to hermit crabs.

The squat lobster Eumunida picta. Video courtesy of the NOAA Office of Ocean Exploration and Research, Gulf of Mexico 2018. Download larger version (mp4, 35.1 MB).

Squat lobsters belong to the phylum Arthropoda. The majority of squat lobsters are found in deeper waters and have very long claws that can be twice as long as their bodies. They have long, waving, whip-like antennae that they use somewhat like cat whiskers, to locate objects and especially to maintain individual distance – the space between one squat lobster and another.

Squat lobsters generally eat small marine worms or crustaceans or scavenge on dead animals. In the Gulf of Mexico where squat lobsters are the dominant decapod (crustaceans having 10 feet) on Lophelia coral banks, they are often seeing with their claws raised up high over the plane of the reef, which could be an important feeding posture. Some squat lobster species that live among larger corals or feather stars may steal some of the protective slime from a coral and eat it, but they will try to warn off intruders on “their” coral by spreading their pincers.

Squat lobsters move freely over bottom surfaces, and often are found hiding beneath ledges or other bottom structures. Their biggest predators are fish.